This Preliminary Information communication provides information to the technician that steps to diagnose and repair vehicles that have a vibration in the 30-40 MPH range. Technician will need to visually inspect the propeller shaft if Pico readings indicate a propeller shaft 1 disturbance. Technician will need to inspect for obvious signs of damage to the propeller shaft, dents, scrapes, and under coating. If the propeller shaft is damaged replace the propeller shaft. If propeller shaft inspection does not indicate any concerns, then record Pico readings with the sensor placed inside the vehicle where the vibration is felt the most. Technician should rotate the propeller shaft 180 degrees at the rear flange and re-evaluate. If propeller shaft re-indexing does not correct concern, see the appropriate section of the latest version of PI1354 and if further assistance is needed see the latest version of PIP5338 prior to contacting General Motors Technical Assistance Center at the number you have been provided for further assistance.
